Aging behavior and modeling studies of unsaturated polyester resin and unsaturated polyester resin-based blends

This chapter deals with various cases of degradation of unsaturated polyester resin (UPR)-based materials (composites with polyester matrices and polyester interpenetrated networks). The consequences of degradation mainly on mechanical and engineering properties are presented from a structure-relationships point of view. Two main kinds of mechanisms are presented, namely physical (chemicals and water penetration) and chemical mechanisms (hydrolysis, radiolysis, photolysis and photooxidation, and thermal oxidation) together with experimental trackers, existing kinetic models, and some of their available parameters. It seems in particular that the lifetime prediction of UPR-based materials submitted to chemical aging remains an open issue due to the nonideality of networks

Crosslink Density Changes during the Hydrolysis of Tridimensional Polyesters

The hydrolysis of almost ideal networks based on macrodiols of average molar mass about 2 kg mol 1, with L¼18 ester groups per chain is studied. Tensile testing is used to evaluate the crosslink density through the statistical theory of rubber elasticity at two temperatures and three values of relative humidity. A kinetic model for ester consumption including an autocatalysis term is proposed and combined with two original approaches for modeling the crosslink density changes. This allows kinetic parameters of hydrolysis to be determined, and very good predictions are obtained for the variations of crosslink density (or elastic modulus) in the three aging conditions considered. The initial curvature of elastic modulus versus time is predicted positive for weak autocatalysis and negative for strong autocatalysis. The obtained conversion ratio at degelation is found to decrease sharply with the number of esters per elastically active chaincontrat de recherche SAFRAN - ART

Caron, Nathalie et Naomi Wulf, eds. - "Les Lumières américaines." Revue Française d’Études Américaines 92 (mai 2002).

Bélan Caroline. Caron, Nathalie et Naomi Wulf, eds. - "Les Lumières américaines." Revue Française d’Études Américaines 92 (mai 2002).. In: XVII-XVIII. Revue de la société d'études anglo-américaines des XVIIe et XVIIIe siècles. N°63, 2006. pp. 204-206

Caron, Nathalie et Naomi Wulf, eds. - "Les Lumières américaines." Revue Française d’Études Américaines 92 (mai 2002).

Bélan Caroline. Caron, Nathalie et Naomi Wulf, eds. - "Les Lumières américaines." Revue Française d’Études Américaines 92 (mai 2002).. In: XVII-XVIII. Revue de la société d'études anglo-américaines des XVIIe et XVIIIe siècles. N°63, 2006. pp. 204-206